An earthquake along the Hayward Fault jolted Bay Area residents out of bed shortly before 3 a.m.
Initially recorded as a magnitude 4.7 temblor, it was quickly downgraded to 4.4.
Though there were no immediate reports of significant damage, the tremor at 2:39 a.m. was felt as short-duration shaking -- typically five seconds or less -- around the Bay Area. Residents close to the epicenter near Berkeley's historic Claremont Hotel reported alarming degrees of shaking. TV meteorologist Roberta Gonzales was among callers who told KCBS that it felt as though their homes were "picked up and dropped." Others described a rolling sensation.
Commuters were advised to expect early-morning delays on BART to allow time for routine track inspections.
USGS geologist David Schwartz says the quake occurred within about a 5-mile section of the Hayward Fault that has been active, with numerous quakes of magnitude 3 to 4 over the past decade.